Two teachers, Maeve and Craig, are marking essays for the International Baccalaureate program. In a 4-hour shift, Maeve is able to mark on average 13.1 essays with a standard deviation of 1.2. In a 4-hour shift, Craig is able to mark on average 12.8 essays with a standard deviation of 0.9. Assume both distributions are Normal. What is the probability that, working at the same time, Maeve and Craig are able to mark at least 27 essays in a 4-hour shift? Answer as a probability (between 0 and 1) to four decimal places.